It should work, however the distance between Okinawa, and the Vonage servers might make the calls sound awful. It really will depend largely on network conditions where he is, and weather or not the military is blocking that type of traffic. Also, if it doesn't work, Vonage doesn't support it.

is japan on the call Asia plan? that might be another possibility. have him call you and then call him right back. if japan is on the call Asia plan and i think they are, then it would be about the same price as you paying for a 2nd adapter.

_________________St. Louis, MOVonage Customer from February 2005 to May 2010ISP: CharterRouter: Linksys RT31P2 (blew up during electrical storm)